The pour point depressant for diesel was prepared by firstly making modifacation of C5 petroleum resin with maleic anhydride, and then modified with octadecanol. Four factors were studied on the influence of freezing point and cold filter plugging point, which are, respectively, the amount of maleic anhydride and initiator, the time of reaction, the temperature of reaction. The result shows that, the best depression capacity of pour point depressant for diesel is acquired with the amount of maleic anhydride is 15%，and the amount of the initiator is 1.0%, and the temperature is 180 ℃ and the time is 3.0 h.

The catalytic oxidation experiments were carried out to prepare the horniness oxidized wax from paraffin wax and polyethylene. The results show that good products can be obtained under the following conditions: reaction temperature 170 ℃, reaction time 7 h, mass ratio of paraffin wax and polyethylene 7∶3, the amount of catalyst 0.01%, the amount of additive 1.0%, the air flow 0.20 m3/h. acid number of the product was 9.82 mg(KOH)/g, saponification number is 79.19 mg(KOH)/g, penetration is 9.2 (0.1 mm), melting point was 87.4 ℃, index of refraction(75 ℃ ) was 1.453 6. As compared with natural hard wax(carnauba wax)，their properties were quite similar each other.